<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style>
        html,body{
            height: 100%;
        }
    </style>
</head>
<body>


<script>

    alert('点我');
    alert('再点我');
    alert('再再点我');
    alert('再再再点我');
    alert('再再再再点我');

</script>

</body>
</html>